MPG

[sweeney1987]

Ah, now i get it Sweeney, thanks, and i suppose anyone attributing the total mpg difference between two completely different cars to be down to just injector type is remarkably intelligent?

Im not saying its just injectors, it was an example, i said comparing two different design engines with different injection systems wondering why theres an mpg difference is stupid
there are many design factors which are all small differences but help mpg wise.
Injectors with varying spray patterns is one for example. Others would be flow of head(almost sure PD engines are crossflow design whereas hdis are not, meaning less efficient flow in combustion chamber) better breathing means more mpg
Turbo difference, again PDs using more efficient VNT turbos meaning better volumetric efficiency in cylinder
oh and gearbox ratios as already mentioned
all small changes which mean better economy and power

and im not saying im remarkably intelligent, just toms a bit silly for wondering why different engine designs have different charachteristics

They're hardly completely different, they weigh the same for a start. And Infact everythings heavier in the golf drive line (dmf, massive thick shafts, big heavy wheels)....and let's face it both cars are boxy and not particularly aerodynamic.

Anyway, fair enough if it is mainly down to the injectors, obviously the inside of those isn't visible lol.


Aircool, I've noticed this too, the HDi actually prefers revs! . The other diesels I've owned would sit just above idle (not labouring) and get good mpg. BUT. I think the difference is the crap HDi turbo isn't blowing extra air in at idle, so you have to drive a bit faster to get the benefit of the non vnt. That's my excuse when I'm caught speeding anyway haha.

not mainly down to injectors, just one example - see above...

Would anyone be interested in how to fit a 406 trip computer to their 306?



Please excuse the shoddy cutting on the panel.

Yes, sounds awesome, how you do it?